Nickel bearing cryogenic welding material and process



United States Patent M 3,195,230 NHJKEL BEAEWG QRYGGENEC WELDENGMATERHAL AND Pltfltlllddl James V. Perla, Plainiield, and Qnarles E.Witherell, Bound Brook, Ni, assignors to The international NickelCompany, ind, New York, NRC, a corporation of Delaware No Drawing. FiledOct. 1, i962, Ser. No. 22.75% 11 Claims. (\Cl. 29- i96) The presentinvention relates to welding material for producing welds and weldmentshaving good low temperature service properties and characteristics and,more "particularly, to steel welding materials for producing cryogenicsteel welds.

it is Well known that flux-coated stick electrodes of the ASTM/AWSClassifications E8015-C2, E8Gl6-C2 and E8018-C2 have been used to weldlow-carbon nickel steel for low-temperature service. While theseelectrodes have provided fairly adequate Weld strength of acceptablesoundness for some purposes, the low temperature notch toughness of theweld metal has been unacceptable in many applications. It appears thatvariations in Welding current and/0r voltage have influenced the notchtoughness of Welds deposited with these electrodes such that Welds madein the vertical or overhead positions often are inferior in toughness towelds made in the flat position at higher current settings. The reasonor reasons for this difference in toughness characteristics with changesin Welding heat caused by changes in current are not completelyunderstood. However, it is believed to be related to the degree ofhomegeneity of the composition of the Weld metal, particularly since thegross chemical analysis of the weld is not significantly affected by thewelding current level within the electrodes useful range. In addition,the compositional factors that influence Weld toughness often are onlydistinguishable on a microscopic scale, if at all. Thus, in many cases,these factors cannot be detected at all by visual appearance, even undervery high magnifications, e.g., 500 diameters (500x), but only throughphysical measurements such as hardness, toughness and strength.

All electrodes of the aforementioned classes comprise a core wire ofrelatively unalloyed low-carbon steel and a suitable flux coatingcontaining metallic nickel, e.g., in the form of a powder, which alongwith the fluxing and slagging ingredients, provides for the addition ofnickel to the weld to prevent brittleness of the weld at lowtemperatures. To be effective in this respect, it appears that thenickel added through the flux coating should mix thoroughly and alloywith the steel from the core Wire under the action of the welding arc.This alloying is dependent upon the heat of the arc and the turbulenceof the weld puddle. Consequently, it would seem that variations in thethermal intensity of the arc will influence the compositional uniformityof the Weld deposit resulting from alloying the coating constituents ofthe electrode with the core wire.

The submerged-arc welding process which aifords a considerably higherrate of weld metal deposit-ion than coated electrodes has also beenuseful to some extent in providing welds and weldrnents for cryogenicapplications. The filler wires used in the submerged-arc process havebeen of relatively unalloyed low-carbon steel which is quite similar tothose used for the aforedescr-ioed coated electrode core wires. In thiscase, as in the case of the coated electrode, the necessary nickeladdition variations in welding current and, because of the wider assPatented July 26,

usable range of welding current and travel speed in submerged-arcwelding, the toughness variations have been correspondingly wider thanin coated electrode welding. Weld cracking has also been a problem withthe submerged-arc process in attempting to deposit welds of adequate lowtemperature toughness. Consequently, this Welding process has not beenWidely used for this purpose.

Attempts to produce a filler wire for either the submerged-arc processor the inert-gas process (including tungsten-arc and metal-arc) or acoated electrode core Wire containing suflicient nickel to produce weldshaving adequate notch toughness at low temperatures have not met withsuccess. The main difiiculty in the use of such welding materials isthat the welds produced therewith have exhibited a tendency to crack.

Thus, While it has been possible to fabricate nickel steel vessels forervice down to about F. below zero (minus 151') F.) using commerciallyavailable matcrials, the procedure has not been thoroughly satisfactorynor has it provided fabricated vessels, etc., having the low temperatureproperties and/ or characteristics currently being demanded by industryfor various appl cation. Coated electrodes have heretofore afforded thebest results. However, the marginal notch toughness, the sensitivity tovariations in toughness with variations in welding current and the lowrate of welding deposition inherent in the coated electrode weldingprocess have been serious drawbacks. While an automatic welding processsuch as the submerged-arc process could increase the rate of deposit ofWeld metal, this process also suiers from the disadvantage of producingwelds having a wide variation in notch toughness. In addition, the weldsproduced using an automatic welding process are crack sensitive. Thus,these deleterious properties and/ or characteristics have materiallyhindercd its use.

Althougl'i many attempts were made to overcome the foregoingdifficulties and other disadvantages, none, as far as we are aware, wasentirely successful when carried into practice on an industrial scale.

It has now been discovered that crack-free welds having good notchtoughness at low temperatures can be produced by employing a specialwelding material contaming special ingredients in controlled amountsunder particular conditions.

It is an object of the present invention to provide a steel weld havinggood cryogenic properties and/or characteristics.

Another object of the invention is to provide a substantially crack-freewelding structure having good notch toughness at low temperatures.

The invention contemplates providing a process for producing asubstantially crack-free weld and/ or welded structure having good lowtemperature caracteristics and/ or properties.

A further object of the invention is to provide a filler metal for usein insert-gas metal-arc Welding which filler metal is particularlyadapted for producing lowtemperature service welds which aresubstantially crac. free.

The invention further contemplates providing a unique inert-gasmetal-arc welding process for producing crackfree, cryogenic welds.

it is another object of the invention to provide a welding material'cularly adapted for producing crack-free welds having notch to nness incombination with good strength at low temperature in the submerged-arcwelding process.

Still another object of the invention is to provide a specialsubmerged-arc Welding process for producing substantially craciefreewelds having good low temperature properties and/ or characteristics.

It is also an object or" the invention to provide a coated electrodehaving a special core wire which electrode is particularly adapted forproducing substantially crack- .free, non-porous welds having good lowtemperature properties and/ or characteristics.

it is likewise within the contemplation of the invention to provide animproved nickel-containing steel electrode which electrode has a fluxcoating containing special proportions of ingredients.

, Among the further objects of the present invention is the provision ofa coated electrode having a flux coating in unique combination with anovel core wire.

It is also a purpose of this invention to provide a novel coatedelectrode Welding process for producing substan tially crack-free weldshaving good notch toughness at low temperatures.

Other objects and advantages will become apparent from the followingdescription.

Broadly stated, the present invention contemplates a welding materialfor use in shielded-arc welding, including arc welding with flux-coatedelectrodes, submerged- .arc Welding, inert-gas metal-arc welding,inert-gas tungsten-arc welding, etc. In general, the welding material,i.e., welding metal, is a low alloy steel which contains, by weight andin addition to any fluxing and slagging ingredients, about 2.5% to aboutnickel, about 0.4% to about 1.5% manganese and about 0.1% to about 0.7%aluminum. In addition to iron, nickel, manganese and aluminum, thewelding metal of this invention may also contain, by weight, up to about0.5% molybdenum, less than about 0.07% carbon, up to about 0.7% siliconand up to about 0.1% calcium. The calcium content is based upon theamount added to the melt in producing the welding metal. The balance ofthe welding metal is substantially iron aside from the usual impuritiesand deoxidants. Advantageously, the welding material is substantiallydevoid of such deleterious elements as phosphorus and sulfur although itcan tolerate up to about 0.02% phosphorus and up to about 0.02% sulfurprovided that the sum of any phosphorus present and of any sulfurpresent is less than about 0.025%.

Nickel, in combination with the other ingredients of theweldingmaterial, is essential to maintaining low temperature toughness in theweld deposit and should not drop below about 2.5% if operability attemperatures below about minus 100 F. are desired for the Weld. On theother hand, as nickel increases beyond about 5%, weld cracking willincrease unless the amount of other elements, particularly sulfur andphosphorus, are substan- Consequently, in orderto produce welds forservice down to about minus 150 F., the nickel content is between about2.5% and about 5% and, advantageously, between about 3% and about 4%.

Manganese in the welding material of this invention is essential toproduce crack-free welds. It aids in the production of substantiallynon-porous weld deposits. Contrary to its beneficial effect of loweringthe impact transition temperatures in wrought alloy steels in amounts upto about 1.5%, considerably smaller additions of manganese decreasenotch toughness (that is, manganese raises the transition temperature)of weld metal. Nevertheless, hot cracking is not substantiallyeliminated particularly in highly restrained welds in heavy platewithout the presence of at least about 0.4% manganese. Consequently, inorder to insure sound weld deposits without materially less than about0.3%, also were prone to porosity which appeared to result fromatmospheric oxygen pickup and an insui'licient level or" deoxidizers inthe weld fusion.

luminum, in combination with the heretofore mentioned other ingredientsof the welding material, is present in amounts of about 0.1% to about0.7%. Aluminum is an efficient deoxidizer in the welding materials ofthis invention and thus contributes importantly to the. production ofsound welds. For example, the presence of 0.1% aluminum is beneficial inobtaining substantial freedom from hot-cracking. On the other hand, ifaluminum is greater than about 0.7%, the welds will lack the degree oflow temperature notch toughness required for service down to about minus150 F. In addition, aluminum acts to obviate the detrimental effects ofmanganese on notch toughness.

While somewhat over 0.1% carbon is normal and beneficial for wroughtsteels of the ASTM A-203 type, this level is excessive for the weldmetal of this invention since at these high levels, the deposited metalis sensitive to weld cracking. The higher carbon contents also lower thetolerable levels of residual phosphorus and sulfur and thereby increasebrittleness. Provided the residual amounts of sulfur and phosphorus arelow, the weld wire may contain as much as about 0.07% carbon withoutdetrimental eitects. Advantageously, the carbon content of the weldingmaterial is below about 0.05%. At these low carbon levels, the weldmetal is sound and substantially free from cracks and it still ischaracterized by satisfactory strength. a

While residual silicon is usually present in the welding material as adeoxidation residual, it is not an essential constituent of the weldingmaterial of this invention since toughness will decrease and the Weldmetal will be cracksensitive.

contain a small amount of silicon, i.e., about 0.1% to about 0.2%, toaid in the deoxidation of the Weld. For

Advantageously, the welding material should example, even though thealloy to be used as the welding material is thoroughly killed, there isa tendency for oxygen to be picked up in the weld metal from theatmosphere and the iiux under the intense heat of the Welding are. Inorder to vitiate the deleterious effects of oxygen on the low.temperature notch toughness of the weld deposit,

adversely affecting low-temperature notch toughness of silicon can beadvantageously employed to fix the oxygen. Molybdenum is also anoptional element and may be present in amounts up to about 0.5% as shownhereinbefore. However, its presence, particularly in submergedarcwelding, offers an advantage in assuring crack-free welds, especiallyunder conditions of severe restraint, without detrimentally afiectingnotch toughness. If molybdenum is present in amounts above about 0.5%,there IS a tendency for the notch toughness to be impaired.

Thus, molybdenum, when present, should not exceed about 0.5%.

When producing the welding metal, calcium may 0ptionally be added to themelt as a deoxidizer. When it is so added, calcium oifers insuranceagainst a high oxideinclusion content in the welding metal which maycarry over to the weld and form stress risers therein which may, undercertain circumstances, initiate micro-fissures and impair weld quality.It is not essential to recover calcium in the melt to derive itsintended benefits.

With respect to phosphorus and sulfur, which are residual impurities,these elements if allowed to increase beyond the limit heretofore shown,increase the sensitivity of the weld metal to hot cracking as well aslowering the notch toughness. Consequently, theserelements should beheld to 0.025% in total.

In carrying the invention into practice, when the weld ing metal is tobe employed in the submerged-arc welding process, advantageous resultswill be obtained when it contains up to about 0.05% carbon, from about0.1% to about 0.2% silicon, from about 3.25% to about 3.75% nickel, fromabout 0.8% to about 1.3% manganese, from about 0.25% to about 0.35%molybdenum, from about 0.1% to about 0.2% aluminum, from about 0.03% toabout 0.07% calcium (added to the melt), less than about 0.01%phosphorus, less than about 0.01% sulfur, the

sum of any phosphorus and any sulfur present being less than about0.015% with the balance substantially iron. Such welding metals arecharacterized by producing welds having a notch toughness of at leastfoot-pounds at minus 150 F. and being substantially crack-free andporosity-free. Molybdenum, as is shown hereinbefore, is advantageouslyincluded in the submerged-arc filler wires of this invention since inthe range of 0.25% to 0.35% it affords increased resistance to weldcracking without detrimentally attesting notch toughness at lowtemperatures. The aluminum in these submerged-arc filler metals isadvantageously less than about 0.2% since greater amounts lead toinclusions of oxides in the Weld deposits. However, at least about 0.1%is essential to provide adequate low temperature toughness to thedeposits as well as assisting in the production of sound deposits. Aparticularly advantageous welding metal for use in submerged-arc weldingprocesses contains less than about 0.05% carbon,

, about 0.2% silicon, about 3.5% nickel, about 1% manganese, about 0.3%molybdenum, about 0.15% aluminum, about 0.05 calcium (added to themelt), less than about 0.01% phosphorus, less than about 0.01% sulfur,the sum of any phosphorus and sulfur present being less than about 0.015with the balance substantially iron.

As was mentioned hereinbefore, the welding material of the presentinvention can be used in coated electrode arc welding and in inert-gasarc welding, e.g., in an inertgas tungsten-arc process or in a processwherein the metal itself is the electrode. In any case, the filler metalused in inert-gas metal-arc welding or as a core wire in coatedelectrode arc welding advantageously contains, by weight, about 3.25% toabout 3.75% nickel, up to about 0.05

carbon, about 0.1% to about 0.2% silicon, about 0.8%

to about 1.3% manganese, about 0.3% to about 0.7% aluminum, about 0.03%to about 0.07% calcium (added to the melt), less than about 0.01%phosphorus, less than about 0.01% sulfur, the sum of any phosphorus plusany sulfur present being less than about 0.015% with the balanceessentially iron. These welding metals are characterized by havingexcellent forgeability and working characteristics and by being readilydrawn into wire. In addition, in use, these welding metals produce soundwelds having notch toughnesses of at least 15 foot-pounds at minus 150F. The aluminum in the core wire of the coated electrode and in thefiller wires for inert-gas welding is present in amounts from about 0.3%to about 0.7% While 0.1% of aluminum is somewhat effective ineliminating weld cracking, at least 0.3% is more advantageous lyincluded when Welds of the highest quality are desired. A particularlyuseful coated electrode core wire or an inert-gas filler wire is onecontaining, by weight, less than about 0.05% carbon, about 0.15%silicon, about 3.5% nickel, about 1% manganese, about 0.5% aluminum,about 0.05% calcium (added to the melt), less than about 0.01%phosphorus, less than about 0.01% sulfur, the sum of any phosphorus andany sulfur present being less than about 0.015% with the balancesubstantially iron.

The welding material of this invention when used as a coated electrodecan include from about to about 50% slag-forming and flux-formingingredients by weight 0 TABLE I Range, percent Flux coating: by weightCalcium carbonate 30 to 70. Cryolite 30 to 70. Bentonite Up to 5.

Other metallurgically neutral fluxes such as the titania types, thelime-fluorspar types, etc., may also be used as those skilled in the artwill readily understand.

The ingredients used in making the flux are advantageously powderedingredients. In general, the mixed ingredients usuaily have a particlesize of between about 60 microns and about 300 microns.

A water-dispersible binder ordinarily is employed with the flux toprovide a durable and hard coating on the core wire after drying andbaking. The binder advantageously is of the silicate type as it producesa durable coating, i.e., a coating that is resistant to mechanicaldamage and that does not require a rebake prior to use. The silicatetype binder may be an aqueous solution of sodium silicate and/orpotassium silicate. Table ll gives the amounts (in parts by weight ofthe dry flux) of ingredients which can be used for the binder. It is tobe appreciated, however, as those skilled in the art will readilyunderstand, that a silicate solution of a dififerent specific gravitythan shown herein also can be used.

trudablc consistency.

The flux coating can be applied to the core wire in any suitable manner,e.g., by an extrusion process, and dried on the wire surface by suitabledrying and/ or baking. This results in a hard adherent coating of highmechanical strength relatively resistant to mechanical damage undernormal handling conditions. A satisfactory drying or baking treatment ofthe flux and binder mixture comprises a normal continuous oven dryingtreatment followed by a baking treatment comprising gradually raisingthe temperature to about 600 F. and holding at that level for about twohours.

Examples of typical coated electrode dimensions (core diameter plus fluxthicknesses) are given in Table Hi.

All dimensions therein contained are in inches.

However, it is permissible, as will be apparent to those skilled in theart, to vary considerably the core diameterwere spaced strap set into a2" thick steel welding table and held in For the purpose of giving thoseskilled in the art a 'better understanding of the invention and a betterappreciation of the advantages of the invention, the followingillustrative examples are hereinafter set forth:

Example 1 A coated electrode was prepared by extruding a suitablelow-hydrogen lime-cryolite type flux coating containing about 50%calcium carbonate, about 47% cryolite and about 3% bentonite on adiameter core wire. The core wire contained, by weight, about 0.05%carbon, about 0.15% silicon, about 3.5% nickel, about 1% manganese,about 0.5% aluminum, about 0.05% calcium, less .than about 0.01%phosphorus, less than about 0.01%

sulfur with the balance essentially iron. The electrode .was given anormal baking treatment at 600 F. for about two hours to dry theextruded coating. was then used to make a butt weld between two platesof This electrode 3 /2% nickel steel as described hereinafter.

The nickel steel plates conformed to ASTM Specification A-203, Grade E,and were of commercial origin.

The chemical analysis of the plate indicated that it contained 0.12%carbon, 0.24% silicon, 0.54% manganese,

33% nickel, 0.013% phosphorus, 0.026% sulfur and balance essentiallyiron. plates were /2 thick, 6 wide and 12" long. The joint Thedimensions of each of the was of the single V-groove type having an 80angle between the members. A lip was provided along the bevelled 12"edge of each plate. The two pieces of plate apart over a grooved copperbacking that position during Welding by six heavy-duty C-clamps, threeon each side.

The Weld was made manually in the fiat position using standardtechnique, without preheat. A maximum interpass temperature of 300 F.was maintained throughout, i.e., the temperature of the deposited metalwas below about 300 F. before the next pass was started. When the jointwas completed, the clamps were loosened and the weldment turned overwith the penetration side facing upward. The root penetration was thenground smooth and all visual unfused areas below the plate surfaceground out and a single sealing weld pass deposited along the amined fordefects using a magnification of 15 diameters. 1

No cracks, porosity, inclusions or defects of any kind were observed inany of the 12 slices. Six of the 12 slices were then given astress-relieving heat treatment consisting of exposure to a temperatureof 1150 F. for

one hour and air-cooled. The other six slices were left in the as-weldedcondition.

Charpy keyhole and V-notch impact specimens of standard design were thenmachined from the 12 slices. The

' keyhole and V-notch specimens were machined in the center of the weldnugget with the axis of the notch runarrears ning perpendicular to theaxis of the weld and in the direction of the plate thickness. These werethen impacttested at minus 150 F. The results of the impact tests areshown in Table V along with the results of tests per- 5 formed onspecimens from a duplicate weld made using a commercial coated electrodeof the ASTM/AWS E8016-C2 type of the same diameter as the coatedelectrode of this invention. Welds l and 2 were deposited with anelectrode of this invention. Welds 3 and 4 were deposited with the priorart electrode.

TABLE V Impact in foot-pounds at minus 150 F.

Weld Impact No. specimen As-welded Stress-relieved type Average 1 RangeAverage 1 Range 27 24 to 30. 52 46 to 57. 25 18 to 29. 39 39. 15. 2 14to 16.5-. 18.3 18 to 18.5. 4 Keyhole 9 8 to 11. 12. 6 9 to 17.5.

1 Average of three tests. 2 All three values were the same.

Example II A butt joint was prepared by machining a U-groove along one12" edge of each of two A" thick x 6" Wide x 12" long plates conformingto ASTM SpecificationA-203, Grade E, of commercial origin. The platecontained, by weight, about 0.1% carbon, about 0.2% silicon, about 0.4%manganese, about 3.4% nickel, about 0.015% phosphorus, about 0.02%sulfur and the balance essentially lron.

The U-groove joint design provided a M1 thick lip at the bottom of thejoint, a 4" root radius, a 30 angle between the members, and a 2 rootspacing. The root pass was first deposited on the back side of the jointand ground smooth to permit contact with the surface of the weldingplaten during the subsequent welding from the top side. With the rootpass in place and its reinforcement ground flush with the plate surface,the joint was turned over and positioned on a 6" thick steel platen-with the U-groove facing upward. The joint was then bolted to theplaten using six heavy U-strap clamps and hardened 1" diameter steelbolts, three on each side of the joint.

The joint was welded by the submerged-arc process under automaticcontrol using a %'diameter filler wire, in coil form, containing, byweight, less than about 0.05% carbon, about 0.2% silicon, abo ut 3.5%nickel, about 1% .manganese, about'0.3% molybdenum, about 0.19%aluminum, about 0.05% calcium (added to the melt), less .than 0.01 eachof sulfur and phosphorus with the balance essentially iron. The flux wasa standard, fused, neutral, siliceous, submerged-arc flux of commercialpro duction which is commonly used for welding steels (designated hereinas Flux A). The weld was completed in fourteen passes. No preheat orpostheat was used and the interpass temperature was held to less than300 F.

throughout.

After welding, the joint was sawed into /2" wide trans- .verse slicesand evaluated as the coated electrode weld described previously inExample I. No cracks, porosity, inclusions or defects of any kind wereobserved in any of the twelve slices examined. Half of these slices werethen stress-relieved as before and both as-welded and stress-relievedsections were machined into Charpy V- notch impact test specimens asdescribed earlier for the coated electrode weld of Example 1. Thespecimens were then impact tested at minus 150 F.

Several other butt welds identical in every respect to the 111's; wereprepared, evaluated and machined into allweld-metal tensile testspecimens, /8 wide side-bend test specimens, and Charpy V-notch impactspecimens. The impact speci ens were tested over a range or"temperatures from room temperature to minus 150 F. The tensile specimensand side-bend specimens were tested at room temperature. I

The results of the impact tests are tabulated in Table VI.

The composition of the weld metal of these welds was determined fromshaper chips removed from the undiluted center portions of the welddeposit and it contained, by weight, about 3.5% nickel, about 1%manganese, about 0.28% molybdenum, about 0.017% aluminum, about 0.035%carbon, about 0.44% silicon, about 0.006% phosphorus, about 0.005%sulfur with the balance essentially iron. From Table VI, it is to benoted that all of the welds had impact strengths of footpounds or highereven at minus 150 F. in the as-welded condition.

To determine the response of the welding wire described hereinbeforewhen used in conjunction with other standard commercial submerged-arcfluxes, three other sets of butt Welds in /4" plate were also prepared.All welds were made using the same Welding conditions and proceduredescribed hereinbefore. The only difierence among the sets of welds wasthe ilux used. A flux used 'for one set of welds is designated as Flux Band was of the agglomerated or bonded type. The all-weld-metal depositsproduced using Flux B contained, by weight, about.3.4% nickel, about 1%manganese, about 0.25% molybdenum, about 0.018% aluminum, about 0.04%carbon, about 0.3% silicon, about 0.006% phosphorus, about 0.01% sulfurwith the balance essentially iron. Another, Flux C, was a fused fluxsimilar to Flux A but one which was developed relatively recentlyspecifically for welding of high strength steels. The composition of theall-weld-metal deposits produced using Flux C was about 3.5% nickel,about 0.9% manganese, about 0.27% molybdenum, about 0.017% aluminum,about 0.04% carbon, about 0.35% silicon, about 0.002% phosphorus, about0.004% sulfur with the balance essentially iron. The other, Flux D, alsoa fused type of low silicon content, was developed within the last yearor so for welding high yield strength ship hull plates. Theall-weld-metal deposits produced using Flux D contained, by weight,about 3.5% nickel, about 0.04% manganese, about 0.27% molybdenum, about0.028% aluminum, about 0.04% carbon, about 0.2% silicon, about TABLE V11Impact, toot-pounds Test Flux temperadcsignation t ugi c, As-wcldedStress-relieved Individual Average Individual Average 32 38,46, 41, 43,4s 50,52,5(153, 5a. 2 ,47 -100 22, 25, 24, 27, 2s. 5 33, as, so, 32

1, 22 as C 74 43, 48 45. 5 57, 66 61. 5 32 46, 45. 5 57, 53. 5 -100 24,22, 18 21. 3 24, 23 23. 5 l50 19, 20, 18 10 20, 22 21 D 74 57, 76 66. 567, 67 67 32 60, 71 65.5 57, 64 60. 5 -100 29, 4s, 53 4o. 7 2s, 37, 27so. 7 -150 20, 32, 41 31 29, 24, 21 24. 7

From Table Vll', it is clear that all of the filler metals or" thisinvention produced weld deposits which exhibited excellent impact valuesat minus 150 F. even in the aswelded condition.

Side-bend tests were conducted on /8" wide transverse slices from thewelds made using Fluxes A and B, to provide data for welds made usingfluxes of both fused and agglomerated types. Two specimens in each oftwo conditions, as-welded and stress-relieved, were subjected to test.The bend tests were conducted by bending the polished and etched weldslices over a 1 /2 diameter steel bar until the legs of the U wereparallel. At that point, the test was stopped and the specimens removedfrom the bend test jig and visually examined at a magnification of 15diameters for defects. No defects of any kind were observed in any ofthe side-bend specimens.

0.357" diameter tensile test specimens were then machined from the Weldmetal obtained from each of the afore-described submerged-arc welds. Theresults of these all-weld-rnetal tensile tests are listed in Table VIII.Identical specimens were tested in the as-welded condition (1) and inthe stress-relieved condition (2). The stresselieved specimens weresubjected to a heat treatment comprising holding the specimens at 1150F. for one hour and then air-cooling.

TABLE VH1 0.2% yield Ultimate Elonga- Reduc- Flux deslgna- Weldconstrength tensile tion in tion in tron dition (p.s.i.) strength 1,perarea,

(p.s.i.) cent percent (1) 09, 300 107, 700 18 53 (2) 98, 200 108, 100 2054 (l) 87, 500 97, 800 23 (2) 91, 500 101, 000 21. 53 103, 600 107, 70023 70 i so, 000 as, 355 21 5s (2) 82, 000 93, 600 28 A nickel steelplate having a composition as heretofore set forth was similarly tensiletested. The plate had a 0.2% offset yield strength of 55,900 p.s.i., anultimate tensile strength of 75,500 p.s.i., an elongation in 1 ofExample III A butt weld, similar to that described in Example I, wasprepared between two A-203 plates (composition shown in Example I), /2 X3 X 6", with the weld run ning in the 6" direction. A diameter fillerrod conanneal-so taining, by weight, less than 0.05% carbon, about 0.15%silicon, about 3.5% nickel, about 1% manganese, about 0.5% aluminum,about 0.05% calcium (added to the melt), less than 0.01% sulfur, lessthan 0.1% phosphorus with the balance essentially iron was used in thegas tungsten-arc process, manually controlled, to produce the weld. Thejoint consisted of a total of eleven passes. A backing shield ofinert-gas was provided during welde ing the root pass to aid penetrationflow and to prevent oxide inclusions. The inert-gas used was argon of acommercial purity.

After welding, the joint was sectioned in to six /2 wide transverseslices which were then polished, etched and visually examined fordefects. No cracks, porosity, inclusions or defects of any kind wereobserved in any of the slices. Half of the slices were stress-relievedby holding at 1150 F. for one hour and then air-cooling while the otherhalf were left in the as-welded condition. The slices were then machinedinto standard Charpy V- notch impact specimens as described previously,and tested at minus 150 F. In the as-welded condition, theall-weld-metal had an average impact value of 27.8 footpounds. In thestress-relieved state, the specimens had an average impact Value of 27.5foot-pounds.

Example IV A butt joint was made between two pieces of nickel steelplate in a manner as described in Example Ill, using a welding wirehaving the same composition as used in making the weld of Example 111.However, the

diameter of the wire was 0.062" and the gas metal-arc process,automatically controlled, was employed in producing the weld joint. Theweld joint design and backing shield were the same as used for the welddescribed in Example 111. The joint was completed in nine passes.

No defects were observed in visual examination at 15 diameters in any ofthe six all-weld-metal transverse slices, which were cut from the joint,after polishing and etching.

Half of the slices were stress-relieved by holding at 1150 F. for onehour and then air-cooling. The other three were left in the as-weldedcondition. The six slices were then machined into standard CharpyV-notch impact specimens and tested at minus 150 F. In the as-weldedcondition, the three specimens had an average impact value of 29.8foot-pounds. In the stress-relieved condition, the three specimens hadan average impact value of 32.5 foot-pounds.

A second inert-gas metal-arc weld identical in all respects to thefirst, except that the weld was 12" in length, was prepared and twoseries of all-weld-metal 0.357 diameter tenside test specimens weremachined therefrom. One series was in the as-welded condtiion, while theother series was in the stress-relieved condition de scribedhereinbefore. The tensile specimens were tested at room temperature withthe results set forth in Table IX.

TABLE 1X These values for ultimate tensile strength and 0.2% offsetyield strength exceed the strengths obtained for the plate material asshown in Example Ill. In addition, the

ductility of the all-weld-specimens are comparable to the ductility ofthe plate material which demonstrates the feasibility of employing thefiller metals of this invention for inert-gas welding.

The present invention is particularly advantageously employed in thefabrication, reconstruction and/or repair of nickel steel vessels, otherstructures, parts, components, etc., used for cryogenic purposes, i.e.,at temperatures as low as minus F. Thus, the welding metals of thepresent invention are especially useful in welding of cryogenic nickelsteels containing, by weight, about 2.25% to about 5% nickel, up toabout 1.5% manganese, up to about 0.15% carbon, up to about 0.5%silicon, with the balance iron. in addition, the welding materials ofthis invention can be used for the welding of mild steel and alloysteels containing, by weight, up to about 12% nickel, up to about 1.5manganese, up to about 0.15% carbon and up to about 0.5% silicon.Another feature of this invention is that the welding metals are usablein any of the commonly used arcwelding processes. In particular, theinert-gas filler wires of the invention are unique in that they may beused in the gas metal-arc and gas tungsten-arc welding processes when itis undesirable to employ a flux such as in depositing a root pass in apipe or vessel where accessibility limitations prevent the removal ofslag. In these situations, the wire has proven to be an ideal materialfor the purpose when formed into backing rings or consumabletemperatures as low as about minus 150 P. which filler Wire contains, byweight, about 3.5% nickel, about 1% manganese, about 0.3% molybdenum,about 0.15% aluminum, less than about 0.05% carbon, about 0.2% silicon,about 0.05% calcium added, less than about 0.01% phosphorus, less thanabout 0.01% sulfur, the sum of any phosphorus and any sulfur presentbeing less tha nabout 0.015% with the balance essentially iron.

2. A submerged-arc filler wire for producing welds having impact valuesof at least about 15 foot-pounds at temperatures as low as about minus150 F. which filler wire contains, by weight, about 3.25% to about 3.75%nickel, about 0.8% to about 1.3% manganese, about 0.25% to about 0.35%molybdenum, about 0.1% to about 0.2% aluminum, less than about 0.05carbon, about 0.1% to about 0.2% silicon, about 0.03% to about 0.07%calcium added, less than about 0.01% phosphorus, less than about 0.01%sulfur, the sum of any phosphorus and any sulfur present being less thanabout 0.015% with the balance essentially iron. I

3. A Welding metal for producing improved cryogenic Weld deposits whichwelding metal contains, by weight, about 3% to about 4% nickel, about0.1% to about 0.7%

aluminum, about 0.8% to about 1.3% manganese, up to about 0.5%molybdenum, less than about 0.07 carbon, up to about 0.7% silicon, upto'about 0.1% calcium added, less than about 0.01% phosphorus, less thanabout 0.01% sulfur, the sum of any phosphorus and any sulfur presentbeing less than about 0.015% with the balance essentially iron.

4. A welding metal for producing improved cryogenic Weld deposits whichwelding metal contains, by weight,

'about 2.5% to about 5% nickel, about 0.1% to about 0.7% aluminum, about0.4% to about 1.5% manganese, 70

up to about 0.5% molybdenum, less than about 0.07% carbon, up to about0.7% silicon, up to about 0.1% calcium added, less than about 0.02%phosphorus, less than about 0.02% sulfur, the sum of any phosphorus andany sulfur present being less than about 0.025% With the balanceessentially iron. 7

5. A nickel steel Welding metal for producing improved cryogenic welddeposits which steel welding metal consists essentially of, by weight,about 2.5 to about nickel, about 0.1% to about 0.7% aluminum, up toabout 0.5% molybdenum, less than about 0.07% carbon, up to about 0.7%silicon, less than about 0.02% phosphorus, less than about 0.02% sulfur,the sum of any phosphorus and any sulfur present being less than about0.025% and about 0.4% to about 1.5 manganese with the balanceessentially iron.

6. A process for producing welds having impact values of at least aboutfoot-pounds at temperatures as low as about minus 150 F. between twonickel steel members which contain, by weight, about 2.5% to 5% nickel,up to about 1.5% manganese, up to about 0.15% carbon, up to about 0.5%silicon, with the balance iron which process comprises melting byarc-welding a welding alloy containing, by weight, about 3% to about 4%nickel, about 0.8% to about 1.3% manganese, about 0.1% to about 0.7%aluminum, up to about 0.5 molybdenum, less than about 0.07% carbon, upto about 0.7% silicon, up to about 0.1% calcium, less than about 0.01%phosphorus, less than about 0.01% sulfur, the sum of any phosphorus andany sulfur present being less than about 0.015% With the balanceessentially iron and depositing said melted welding alloy between thenickel steel members.

- 7. A process for producing sound, cryogenic ironnickel weld depositson a ferrous member which comprises providing a coated welding electrodehaving a core wire containing, by weight, about 3.25 to about 3.75%nickel, about 0.1% to about 0.2% silicon, about 0.8% to about 1.3%manganese, about 0.3% to about 0.7% alumi num, up to about 0.05% carbon,about 0.03% to about 0.07% calcium added, less than about 0.01%phosphorus, less than about 0.01% sulfur, the sum of any phosphorus andany sulfur present being less than about 0.015 With the balanceessentially iron and having a flux containing, by weight, about 30% toabout 70% calcium carbonate, about 30% to about 70% cryolite and up toabout 5% bentonite, melting said coated electrode and depositing byarc-welding on said ferrous member a metal weld deposit containing, byWeight, about 2.5 to about 5% nickel, about 0.2% to about 1.5 manganese,about 0.01% to about 0.5% aluminum, up to about 0.5% molybdenum, up toabout 0.5% silicon, up to about 0.07% carbon, up to about 0.01% calcium,less than about 0.02% phosphorus, less than about 0.02% sulfur, the sumof any phosphorus and any sulfur present being less than about 0.025%With the balance essentially iron.

8. A process for producing welds having impact values of at least about15 foot-pounds at temperatures as low as about minus 150 F. on at leastone ferrous member which comprises providing a submerged-arc fillermetal containing, by weight, about 3.25 to about 3.75% nickel, about0.8% to about 1.3% manganese, about 0.25% to about 0.35% molybdenum,about 0.1% to about 0.2% aluminum, less than about 0.05% carbon, about0.1% to about 0.2% silicon, about 0.03% to about 0.07% calcium added,less than about 0.01% phosphorus,

less than about 101% sulfur, the sum of any phosphorus and any sulfurpresent being less than about 0.015% with balance essentially iron andmelting said filler meta-l by arc-Welding and depositing the meltedmetal in the presence of a metallurgically neutral flux containingfluxing and slagging ingredients to produce a Weld containing, byweight, about 2.5% to about 5% nickel, about 0.2% to about 1.5%manganese, about 0.01% to about 0.5% aluminum, up to about 0.5molybdenum, up to about 0.5% silicon, up to about 0.07% carbon, up toabout 0.01% calcium, less than about 0.02% phosphorus, less than about0.02% sulfur, the sum of any phosphorus and any sulfur present beingless than about 0.025% with the balance essentially iron.

9. A process for producing welds having impact values of at least about15 foot-pounds at temperatures as low as about minus 150 F. on at leastone ferrous member which comprises providing a filler metal containing,by Weight, about 3.25% to about 3.75% nickel, up to about 0.05% carbon,about 0.1% to about 0.2% silicon, about 0.8% to about 1.3% manganese,about 0.3% to about 0.7% aluminum, about 0.03% to about 0.07% calciumadded, less than about 0.01% phosphorus, less than about 0.01% sulfur,the sum of any phosphorus and any sulfur present being less than about0.015% with the balance essentially iron and melting said filler wireand depositing the melted metal on said ferrous member in an inertatmosphere to produce a Weld containing, by weight, about 2.5% to about5% nickel, about 0.2% to about 1.5% manganese, about 0.01% to about 0.5aluminum, up to about 0.5% molybdenum, up to about 0.5% silicon, up toabout 0.07% carbon, up to about 0.01% calcium, less than about 0.02%phosphorus, less than about 0.02 sulfur, the sum of any phosphorus andany sulfur present being less than about 0.025% with the balanceessentially iron.

10. A Welding metal for use in coated electrode and inert-gas arcwelding containing, by Weight, about 3.5% nickel, about 1% manganese,about 0.5% aluminum, about 0.05 calcium added, less than about 0.05%carbon, about 0.15% silicon, less than about 0.01% phosphorus, less thanabout 0.01% sulfur, the sum of any phosphorus and any sulfur presentbeing less than about 0.015 with the balance essentially iron.

11. A welding metal for use in coated electrode and inert-gas arcwelding containing, by weight, about 3.25% to about 3.75% nickel, up toabout 0.05% carbon, about 0.1% to about 0.2% silicon, about 0.8% toabout 1.3% manganese, about 0.3% to about 0.7% aluminum, about 0.03% toabout 0.07% calcium added, less than about 0.01% phosphorus, less thanabout 0.01% sulfur, the sum of any phosphorus and any sulfur presentbeing less than about .0015 with the balance essentially iron.

References Cited by the Examiner UNITED STATES PATENTS 2,140,237 12/38Leitner. 2,744,036 5/56 Pease et al. 117-206 3,097,294 7/ 63 Kubli etal. -124 JOHN F. CAMPBELL, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,195,230 July 20, 1965 James V. Peck et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 2, lines 22 and 23, for "application" read applications column11, line 4, for "0.1%" read 0.01% line 12 for "in to" read into line 51,for "tenside read tensile same column 11, line 52, for "condtiion" readcondition column 12, line 42, for "tha nabout" read than about column14, line 1 for 01%" read 0.01% line 3, before "balance" insert the line33, for "0.02" read 0.02% same column 14, line 54, for ".00l5%" read 0015% Signed and sealed this 12th day of April l966 (SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. A SUBMERGED-ARC FILLER WIRE FOR PRODUCING WELDS HAVING IMPACT VALUESOF AT LEAST ABOUT 15 FOOT-POUNDS AT TEMPERATURES AS LOW AS ABOUT MINUS150*F. WHICH FILLER WIRE CONTAINS, BY WEIGHT, ABOUT 3.5% NICKEL, ABOUT1% MANGANESE, ABOUT 0.3% MOLYBDENUM, ABOUT 0.15% ALUMINUM, LESS THANABOUT 0.05% CARBON, ABOUT 0.2% SILICON, ABOUT 0.05% CALCIUM ADDED, LESSTHAN ABOUT 0.01% PHOSPHORUS, LESS THAN ABOUT 0.01% SULFUR, THE SUM OFANY PHOSPHORUS AND ANY SULFUR PRESENT BEING LESS THAN ABOUT 0.015% WITHTHE BALANCE ESSENTIALLY IRON.
 6. A PROCESS FOR PRODUCING WELDS HAVINGIMPACT VALUES OF AT LEAST ABOUT 15 FOOT-POUNDS AT TEMPERATURES AS LOW ASABOUT MINUS 150*F. BETWEEN TWO NICKEL STEEL MEMBERS WHICH CONTAIN, BYWEIGHT, ABOUT 2.5% TO 5% NICKEL, UP TO ABOUT 1.5% MANGANESE, UP TO ABOUT0.15% CARBON, UP TO ABOUT 0.5% SILICON, WITH THE BALANCE IRON WHICHPROCESS COMPRISES MELTING BY ARC-WELDING A WELDING ALLOY CONTAINING, BYWEIGHT, ABOUT 3% TO ABOUT 4% NICKEL, ABOUT 0.8% TO ABOUT 1.3% MANGANESE,ABOUT 0.1% TO ABOUT 0.7% ALUMINUM, UP TO ABOUT 0.5% MOLYBDENUM, LESSTHAN ABOUT 0.07% CARBON, UP TO ABOUT 0.7% SILICON, UP TO ABOUT 0.1%CALCIUM, LESS THAN ABOUT 0.01% PHOSPHORUS, LESS THAN ABOUT 0.01% SULFUR,THE SUME OF ANY PHOSPHORUS AND ANY SULFUR PRESENT BEING LESS THAN ABOUT0.015% WITH THE BALANCE ESSENTIALLY IOR AND DEPOSITING SAID MELTEDWELDING ALLOY BETWEEN THE NICKEL STEEL MEMBERS.